I have the opportunity to run Furuno on large platform vessels while working my "day" job and it's obviously the gear that mariners world-wide depend on for their livelihood, not to mention their lives.
That said, I place that same level of reverence, respect and reliability upon Simrad and I know Robbo feels the same way about his Lowrance gear.
With regard to sonar performance on your particular vessel: The single biggest factor is TRANSDUCER INSTALLATION!
Your choice of transducer model, type (transom mount or thru-hull), frequency and the output power far outweighs the brand of gear.
One last thought: I install ALL of my marine electronics and so does Robbo.
Installing your own gear teaches you things about the gear, about your boat and about your boat's electrical system.
By installing your own gear, if you ever have an issue on the water at the very least, you'll know where to look....